AUTHOR=Koh Eugene , Brandis Alexander , Fluhr Robert 

TITLE=Plastid and cytoplasmic origins of 1O2-mediated transcriptomic responses

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.982610

DOI=10.3389/fpls.2022.982610

ISSN=1664-462X

ABSTRACT=<p>The reactive oxygen species singlet oxygen, <sup>1</sup>O<sub>2</sub>, has an extremely short half-life, yet is intimately involved with stress signalling in the cell. We previously showed that the effects of <sup>1</sup>O<sub>2</sub> on the transcriptome are highly correlated with 80S ribosomal arrest due to oxidation of guanosine residues in mRNA. Here, we show that dysregulation of chlorophyll biosynthesis in the <italic>flu</italic> mutant or through feeding by δ-aminolevulinic acid can lead to accumulation of photoactive chlorophyll intermediates in the cytoplasm, which generates <sup>1</sup>O<sub>2</sub> upon exposure to light and causes the oxidation of RNA, eliciting <sup>1</sup>O<sub>2</sub>-responsive genes. In contrast, transcriptomes derived from DCMU treatment, or the <italic>Ch1</italic> mutant under moderate light conditions display commonalties with each other but do not induce <sup>1</sup>O<sub>2</sub> gene signatures. Comparing <sup>1</sup>O<sub>2</sub> related transcriptomes to an index transcriptome induced by cycloheximide inhibition enables distinction between <sup>1</sup>O<sub>2</sub> of cytosolic or of plastid origin. These comparisons provide biological insight to cases of mutants or environmental conditions that produce <sup>1</sup>O<sub>2</sub>.</p>